If the tires are worn unevenly, if the vehicle is not stable on the highway or if the handling seems uneven in spirited driving, the wheel alignment should be checked. If an alignment problem is suspected, first check for improper tire inflation and other possible causes. These can be worn suspension or steering components, accident damage or even mismatched tires. If any worn or damaged components are found, they must be replaced before the wheels can be properly aligned. Wheel alignment requires very expensive equipment and involves minute adjustments that must be accurate; and should only be performed by a trained technician. Take your vehicle to a properly equipped shop.
The alignment angles that apply to the front wheels also apply to the rear wheels. The following is a description of the alignment angles, which are adjustable on A4 and Passat vehicles and how they affect vehicle handling.
On 1990-97 Passat front wheel drive models, the front camber and toe are adjustable. Because the rear axle is essentially a beam, the toe can be equalized but not adjusted individually for each wheel.
On A4 and 1998-00 Passat front wheel drive models, the front camber can be equalized and toe-in adjusted with the vehicle unladen and raised. As with earlier models, the toe can be equalized but not adjusted individually for each wheel.
On A4 and 1998-00 Passat All Wheel Drive (AWD) models, the front camber can be equalized and toe adjusted with the vehicle unladen and raised. The rear toe and camber can be adjusted individually for each wheel.
On all A4 and 1999-00 Passat models the front toe must also be checked at normal ride height as well as at a specific raised vehicle height depending on the installed suspension version. Obtaining the proper toe in on these models may require that the tie rod end (track rod) be moved up or down in the bearing housing (knuckle) to achieve the correct ride height toe.
Note that the front caster cannot be adjusted on either the A4 or the Passat models. During an alignment, if a caster related problem is discovered, the front subframe can be moved slightly in an attempt to equalize the caster, however if the caster is beyond an acceptable range, the vehicle should be inspected for damaged or worn components.